COLLADA export- Model imports into Prefab3D rotated

Hi everyone!

Ok, I have a model and I have exported it as a COLLADA file (.dae) and managed to get it into Prefab3D. However when it is imported into Prefab3D it comes in essentially lying on its side.

I have set all the transforms to zero and the model is not rotated in the original file and yet still he is flipped on his side. I can change the rotation in PreFab/ Flash but I would much rather get the export happening correctly rather than trying to work with skewed values later.

I’m assuming this just has something to do with a rotation that happens during the export stage but I cannot find anything on the internet that can help me solve this issue. So if anyone knows a way to solve this, that would be fantastic thanks!

One work around I’ve used is to rotate your model in edit mode enough to counter what your final program is doing after export.

Ahh that is a good work around. Thanks a lot Redikann, I’ll try that soon.

I think it has to do with the differences in coordinate frames between software packages. For example, in OpenGL, y is up, x is right, and z points toward the camera. In Blender, y points away from the camera, x is right, and z is up. So things can get rotated if you don’t specify which way is up.

Unfortunately, the ‘up’ direction is hard-coded into the Blender COLLADA exporter. If you look at the exporter source code, it’s hard-coded to have Z point upwards. http://git.blender.org/gitweb/gitweb.cgi/blender.git/blob_plain/HEAD:/source/blender/collada/DocumentExporter.cpp (in the function ‘exportCurrentScene()’, about halfway through the function) I’m not sure why this is the case because almost every other export formats allow you to specify which way is up (3DS, FBX, OBJ, DirectX, x3d, PLY, and STL). I don’t think it would be terribly difficult to add this option to the COLLADA export options.

it’s not with prefab3d (i’ve never used that program) but when i import obj models into blender they often come in “nose down” and need a 90 degree rotation. i don’t know if you’ve tried it but i would really just advise rotating the model in blender to cancel the rotation that gets done to it later, all this is something to do with the way different formats define there axes but as soon as you know the problem you can just perform the precise steps to undo it before exporting.